Establishment of new process technology for EUV lithography

Abstract

Resolution, line edge roughness (LER) and sensitivity (RLS) and defectivity are the well-known critical issues of extreme ultraviolet (EUV) lithography. To break the RLS triangle, metal oxide resist (MOR) is a promising candidate. However, further improvement of MOR process is required for high volume manufacturing to maintain low defectivity. In this paper, conventional and new processes for MOR pitch 32 nm line and space (L/S) and 36 nm pillar patterns was investigated. This new process was able to perform good sensitivity without degrading roughness. In addition, further optimization for underlayer and developer process could mitigate pattern collapses. MOR treatment was evaluated as another technique for roughness improvement. At last, bottom scum defect would be reduced by new process.